1. Field of the Invention
The present invention is directed to construction and use of a multi-shelled gamut boundary descriptor for a device, particularly a source device, for which a gamut boundary descriptor does not already contain a sufficient number of shells.
2. Description of the Related Art
The need for gamut mapping arises during reproduction of colors rendered on one device and/or medium onto another device and/or medium. The difference in gamuts between these devices and media requires re-mapping of colors such that colors in the source gamut are mapped to colors within the destination gamut.
In gamut-mapping where high dynamic range (HDR) imagery and HDR devices are involved, it has been found that a gamut mapping algorithm (GMA) that employs a multi-shelled gamut boundary descriptor (GBD) often yields improved gamut-mapped results and increased color fidelity. See U.S. Patent Application Publication 2005/0047648, “Color Descriptor Data Structure” by Newman, et al., and U.S. Patent Application Publication 2005/0047654 “Gamut Mapping Between Multiple Boundary Regions” by Newman, et al. These published applications are incorporated herein by reference.
Typically, two shells are employed: an inner “reference” shell and an outer “plausible” shell. In general, gamut mapping using such a two-shelled GBD acts to map colors for the inner reference shell of the source device to the inner reference shell of the destination device, and to map colors for the outer plausible shell of the source device to the outer plausible shell for the destination device.
To benefit from the advantageous effect of multi-shelled gamut mapping, both the source device and the destination device must have a multi-shelled GBD. However, there are quite a few devices, such as legacy devices, for which the GBD has an insufficient number of shells, such as devices that have only a singly-shelled GBD. In recognition of this fact, the inventor herein has recently filed a patent application that describes construction of multiply-shelled GBDs for devices that have an insufficiently-shelled GBD, based on the known shells of such devices. See U.S. application Ser. No. 11/220,751, entitled “Perceptual Gamut Mapping With Multiple Gamut Shells” by Siu Kei Tin. The contents of the aforesaid application Ser. No. 11/220,751 are incorporated herein by reference.